Conventional vacuum folders according to the teachings of Christman U.S. Pat. No. 1,974,149 and Nystrand U.S. Pat. No. 3,689,061 include an anvil roll and coacting knife roll to cut segments which are transferred to a carrier roll.
In prior art folders, anvil roll vacuum holds, rotates, and uplifts the leading portion of a segment while a carrier roll holds, rotates the remaining portion with vacuum ports along a transverse line at the midpoint and advances the trailing portion until a fold is completed.
Current products, for example, luncheon and dinner napkins have nominal sizes of about 12xc3x9712xe2x80x3 and 17xc3x9717xe2x80x3 respectively, and typically, rolls used for folding usually have two repeat lengths around the circumference (2-time) for a range of roll diameters from about 8xe2x80x3 to almost 11xe2x80x3 for wider machines.
In state of the art folders, coacting roll pairs in this typical range are made from solid roll blanks drilled from one or both roll ends to provide vacuum conduits which communicate with surface ports and a vacuum source.
Because a pair of vacuum rolls must cooperate to complete a fold, a ratio of anvil:carrier roll diameters of 1.0 to 1.5 generally provides good folding results, but also defines roll and resultant folder limitations. For example, within this range of ratios, rolls have limited length and xe2x80x98workingxe2x80x99 face width, limited cross sectional area requiring limited conduit size and vacuum suction, limits to the length of drilled holes for a pre-selected diameter, diminished vacuum suction in the middle lanes of multi-width machines, and less rigidity to insure proper shearing pressure between anvils and blades without excessive deflection.
Dynamic vibrations at speeds above 250-300 rpm can cause uneven cuts at segment ends.
In present folders, maximum rotary speed is limited primarily because of limited diameters and restricted cross sectional area of conduits that limit vacuum suction. Maximum roll widths for a 2-time roll are primarily limited by vacuum force, deflection and dynamic vibrations.
Total folder production at maximum speed is limited to the maximum roll length without deflection or vibration, and the maximum folder width (roll length) determines the total number of products processed per unit of time from parallel delivery lanes.
Artisans and the prior art do not explain how solid rolls with drilled conduits can be lengthened or how deflection can be avoided without increasing roll diameters and adding substantial weight requiring heavier frames, bearings, drive Hp, and related higher material costs, etc.
The invention solves these contrary and vexing requirements by describing hollow carrier cylinders having internal closed conduit shapes in combination with standard diameter solid anvil/knife rolls supported by intermediate framework in several arrangements described below.
In the preferred embodiment of FIG. 1, a large diameter carrier cylinder with interior conduits coacts with two or more juxtaposed, circumferentially spaced cutoff units having standard solid rolls for feed, cutoff and placement of segments at full web speed.
In another embodiment of FIG. 8, a web is advanced at full speed, slit to product widths, and a plurality if 1-wide juxtposed cutoff units are mounted for transverse support by cross members between side frames to cut and transfer product width segments to a large diameter multiwidth carrier cylinder.
In another embodiment of FIG. 13, full width pluraltiies of cutoff units are arranged along at least two transverse spaced lines and accept product width slit webs at slower speed to cut and transfer segments to alternate surfaces of the cooperating carrier cylinder.
Folders with wider hollow carrier cylinders and standard anvil/knife rolls can now match the width of webs ex-paper machine and thus eliminate pre-converting slit and rewind processing of parent rolls used by the folders.
In addition, by metering a plurality of webs to advance at at slow speed from two or more cutoff units, one or more additional parent rolls are added to increase the run time of each parent roll and the time between parent roll changes thereby increasing machine xe2x80x98uptimexe2x80x99 and productivity per shift.
Beneficial results from this invention include production of stacks having alternating colors and other color combinations as described in U.S. application Ser. No. 09/576060.
This Continuation-in-Part application defines a combination of folding apparatus elements, some previously described in co-pending U.S. patent applications Ser. No. 09/4,811,108, U.S. Pat. No. 6,350,223, Ser. No. 09/499,242 and Ser. No. 09/576,060.
The folding apparatus described herein includes a carrier cylinder with internal conduits of U.S. application Ser. No. 481108, solid anvil rolls as practiced in state of the art machines, anvil roll support means intermediate the side frames according to the teaching of Ser. No. 09/499242, and cutoff unit arrangements not heretofore used in prior art folding apparatus.
In summary, an object of this invention is to provide a hollow carrier cylinder with internal conduits to apply vacuum to a transverse line of ports under the midway fold line between segment ends.
Another object is to provide a folding apparatus having a carrrier cylinder with formed ir pre-molded internal conduits conduits attached to the inside surface and coacting with a standard solid anvil roll having vacuum conduits drilled according to current practice.
An object is to provide rolls having a ratio of diameters between the solid anvil roll and a larger diameter carrier cylinder wherein rotation of a solid anvil roll is about 90 degrees maximum from the nip between the anvil and carrier rolls to insure proper foldover while the carrier advances the trailing panel one half the unfolded product length.
Another object is to provide carrier cylinder internal vacuum conduits with increased area and capacity to allow for larger vacuum apertures in the surface.
An object of this invention is to provide anvil rolls having an operable ratio of diameters with the coacting carrier cylinder and maintaining the same roll ratio for processing webs of different widths.
A further object is to provide 1-wide cutoff assemblies including anvil rolls with drilled vacuum conduits and having a frame width that does not exceed the longitudinally folded web width by more than about 4xe2x80x3
Another object is to provide cutoff unit side frames having vacuum groove retention flanges that do not extend beyond the outer roll surface of an anvil roll mounted therein.
Another object is to provide a vacuum source connection perpendicular to the axis of vacuum conduits.
An object of this invention is to provide interchangeable and standardized metering/cutoff units for transverse mounting of a plurality including one cutoff unit per folded web.
Another object is to provide an intermediate cross frame support and a carrier roll wider than the web being processed to allow for future addition of additional cutoff units to process wider than original webs.
In a related embodiment, an object of this invention is to provide a carrier cylinder of sufficient diameter without excessive weight such that a second plurality of cutoff units (metering, anvil, knife rolls) can be mounted for operation along a second transverse line circumferentially spaced at least one carrier repeat surface from the first plurality.
Another object is to provide internal carrier cylinder conduits to complete a single transverse fold along one or more transverse lines in cooperation with a vacuumized anvil roll and a second transverse fold by air blast through apertures in the carrier surface in cooperation with a non-rotating folding plate.
Another object is to provide two or more between frame supports and two or more pluralities of single product width cutoff units to cut segments from alternate webs being fed at speeds slower than the surface speed of the anvil roll in order to prolong the run time for each of two or more parent rolls being used.
An object of this invention is to provide for a running adjustment of cutting contact between the coacting knife and anvil blade (s).
A further object is to provide a movable support means for nip and running adjustment between the anvil roll and the carrier cylinder
An object of this invention is to provide coacting 2-time anvil and knife rolls having only a single anvil and knife coacting each revolution to extend the blade life and minimize adjustment frequency between rolls.
Other advantages and objects are illustrated and described in the ensuing specifications.